Field of the Invention
The invention generally relates to the field of cleaning interiors of receptacles and installations and, more particularly, toward a method and a device for removing deposits in the interiors of receptacles and installations, by way of explosion technology.
Description of Related Art
The device and method serve for cleaning dirty and slagged receptacles and installations with caking on their inner walls, particularly incineration installations.
Heating surfaces, e.g. of waste incineration plants or generally incineration boilers are generally exposed to large contamination or fouling. This fouling has inorganic compositions and typically arises due to deposits of ash particles on the wall. Coatings in the region of high flue gas temperatures are mostly very hard, since they remain stuck to the wall in either molten form or are melted on the wall or are stuck together by way of substances melting or condensing at a lower temperature, when solidifying on the colder boiler wall. Such coatings are very difficult to remove and are inadequately removed by way of known cleaning methods. This leads to the boiler having to be being periodically taken out of service and cooled for the purpose of cleaning. For this, the construction of a scaffold in the furnace or kiln is often necessary, since such boilers usually have extremely large dimensions. This moreover requires an operational interruption of several days or weeks and is extremely unpleasant and unhealthy for the cleaning personnel due to the large occurrence of dust and dirt. One consequence, which mostly inherently occurs with an operational interruption of an installation, is damage to the container materials themselves as a result of the large temperature changes. The installation standstill costs due to the production or income losses are an important cost factor, additionally to the cleaning and repair costs.
Conventional cleaning methods, which are used when the installations are shut down, are, for example boiler beating, as well as the use of steam jet blasters, water jet blasters/soot blasters or shot-cleaning as well as sand blasting.
Moreover, a cleaning method is known, with which the cooled-down or the hot boiler, which is in operation, is cleaned by way of introducing and igniting explosive bodies. The heat surface caking is blown away due to the impact of the detonation, as well as due to the wall oscillations produced by the shock waves. The cleaning time can be significantly shortened with this method, in comparison to the convention cleaning methods.
The disadvantage with this method is the necessity for explosives. Apart from the high costs for the explosive material, a huge expense with regard to safety must be met, for example with the storage of the explosive, in order to avoid accidents or theft.
A further cleaning method is known from EP 1 362 213 B1, which likewise makes use of means for the production of an explosion. Instead of explosive, according to this method however, a container envelope, which is inflatable with an explosive, gaseous mixture, is attached onto the end of a cleaning lance. The explosive, gaseous mixture is produced from at least two gaseous components.
The cleaning lance together with the empty container envelope is introduced into the boiler space and is positioned in the proximity of the location to be cleaned. Subsequently, the container envelope is inflated with an explosive gas mixture. An explosion is produced by way of igniting the gas mixture in the container envelope, and the shock waves of this explosion lead to the detachment of fouling on the boiler walls. The container envelope is shredded and combusted by way of the explosion. It therefore represents a consumable material.
This method and the associated device compared to the explosive technology with explosive and which is mentioned above, has the advantage that the method is favourable with regard to operation. Thus, e.g., the starting components of a gas mixture, which comprises oxygen and a combustible gas, is inexpensive in procurement in comparison to explosives. Moreover, the procurement and handling of the mentioned gases, in contrast to explosives requires no special permits or qualification, so that anyone with a suitable training can carry out the method.
Moreover, it is also advantageous that the starting components are fed to the cleaning lance via separate feed conduits, and the dangerous explosive gas mixture is therefore not created in the cleaning lance until shortly before triggering the explosion. In comparison to explosives, the handling of the individual components of the gas mixture is indeed far less dangerous, since these individually at the most are combustible, but not explosive.
The associated method has the disadvantage that the filling procedure is comparatively slow. This is due to the fact that the gaseous components are introduced out of pressure containers via metering fittings. The gaseous components are hereby made available in the pressure containers in quantities according to the stoichiometric ratio. The emptying of the pressure containers however requires comparatively much time. Thus the exit speed of the gaseous components from the pressure containers or tanks approaches zero in an asymptotic course with an increasing emptying of the pressure containers. This means that the introduction of the gaseous components into the container envelope takes a comparatively disproportionate amount of time, in particular towards the end of the filling procedure.